What is the Maker now?

Yes, confirmed in Veilguard via Solas's memories.

Andraste taught that the Maker was the force behind creation. First he created the Fade and its denizens, the spirits, and then the material world, presumably embodied in the Titans and mortals. This can still be true. The Chant teaches that the spirits grew envious of what they could see in the material world and wanted a part of it. This could fit with the spirits that became elves crossing over into Thedas and started to create things there with magic, including their own bodies. This disturbed the Titans that reacted almost instinctively, so it would seem Mythal and Solas corrupted them. It would also fit with Andraste saying that magic was a gift of the Maker and it was its abuse that she condemned, likely Mythal feeling guilt over what she had done and what it led to. The biggest abuse was the corruption of the Golden City, which Andraste seemed to think was the source of creative power and where the spirits originated. This may also have been referring in some way to what was done to the Titans. The interior of the uncorrupted Titan in the Descent made me recall descriptions of the Golden City, so one could have been mirroring the other. The majority of religions in Thedas consider the Golden City was the home of their gods.

There is strong evidence that the first Divine, who compiled the Chant, was likely discriminatory in what she included in it. Since Drakon wiped out all Andrastrian cults that did not agree with his own "vision", likely the bits that were left out were lost with them. When it was political expedient to include the elves, the Divine approached the Dalish to get their oral tradition concerning Shartan. There are also other traces of elven teaching in the Chant where it refers to the Beyond, which was the elven term for the Fade. Then when it suited the political narrative to exclude the elves, the Canticle of Shartan was removed and the only reference to him is as the Liberator who tried to save Andraste. Then when Tevinter broke away, the Divine removed the Canticle of Silence from the Chant, claiming it was political rhetoric by Hessarian and not Andraste's words. This may have been true but it does show how the Chant was messed with down the years from the time of Andraste. What other teaching may have been added for political expediency or altered or excluded over the years because it didn't suit the southern Chantry's political agenda?

The words of Morrigan are ambiguous but I don't think she meant Andraste was a vessel of Mythal. However, Mythal could have been the "Maker" who spoke to Andraste, just as she was likely the Lady of the Skies who spoke to Tyrdda Brightaxe. In both cases the mortal mage had a spirit bride/spouse to whom they gave their true devotion, although needing a mortal husband in order to continue their line. Mythal probably was trying to develop a mortal line that would eventually be suitable for her to take up possession. So, Tyrdda broke away from the Alamarri and founded the Avvar, had a daughter by a dwarven prince, her later descendant being Morrighan'nan, who led the Avvar against the Alamaari chieftan Luthias Dwarfson the same year as the 1st Blight began in northern Thedas. Whilst both were slain in the battle, that doesn't exclude the possibility that Morrighan'nan did have daughters who succeeded her and continued her line, likely resulting in Andraste, who was the daughter of an Alamaari chieftan and a Ciriane Queen (who had a magical elven sword in her possession), later marrying an Avvar chieftan, Maferath, and having a daughter who married a Tevinter mage and continued her line. Each succeeding generation only had daughters and I wouldn't be surprised if Flemeth was a product of this line. When she called upon the spirits of the Fade for assistance, instead of receiving guidance, the spirit offered to join with her instead and give her the benefit of the power she had regained over the years. That spirit was Mythal. It should also be noted that somehow traces of an ancient text that was discovered in the Temple of Mythal were also found in an Alamarri war poem and a Denerim lullaby. This suggests that there was some interaction between the ancient elves and the humans in that area, hardly surprising seeing as the area of the Dales and the Frostback Mountains would seem to have been Mythal's domain.

So, essentially, it is still possible to believe there is a Creator god that for want of a better term can be called the Maker. Mythal would have known this to be the case, so likely assumed its identity when speaking with Andraste in order to impress on her the uniqueness of her vision. Andraste had been calling on any god to aid her in freeing her people of oppression, so it is hardly surprising that Mythal would have answered her. On the march north to liberate the slaves of Tevinter from their corrupt leaders (who had risen to power off the discovery of elven artifacts left from the elven empire and the whispers from the Fade of the imprisoned Evanuris and their minions). When her army joined up with that of Shartan, the aim according to the Canticle of Shartan was to liberate their respective people. Andraste named Shartan her Champion after he and his elves saved the day at the Battle of Valarian Fields. After that the crusade started to unravel. Maferath may have genuinely thought they were over stretching themselves after the near disaster of the Valarian Fields, or possibly he was being influenced by a denizen of the Fade, possibly without even being aware of it.

Unfortunately, whilst it is possible to reconcile the various threads of the religion of the Maker as I have done, DAV didn't really bother to do this and just left it up to the player to try and make sense of it. Nor were the various individuals in world as troubled as you would expect them to be by everything that occurred and was revealed in DAV. Since the secret ending put the cat among the pigeons totally when it comes to past history, I think the current writers aren't particularly bothered with previous lore when it comes to making sense of the narrative.

Pretty sure the building the wardens are set up in is the town chantry.