Hi all
Looking for a good turn based strategy game to get into.
Any recommendations from recent games?. Needs to have decent to good AI.
Of course available on GOG

I'm not sure how recent you mean, but the Firaxis XCOM games might be one of the best games on offer on GOG - turn-based strategy or otherwise. (I mean XCOM Enemy Within and XCOM 2 with War of the Chosen expansion.)

Phoenix Point is a XCOM-like indie game that is more recent, and some would say innovative. It cannot compete with the production values and storyline of XCOM, but it is very enjoyable. Dark, more sandbox-like and the free aim system (or targeting specific limbs/areas) is an improvement on the usual formula.

That's XCOM baby! Or at least, those types of games that I can recommend and have played (a lot).

4x: Old World. Latest game in the Civilization lineage. Comes from Soren Johnson's team [known as lead on Civ4 and co-lead of Civ3]. I really dig its "command points" system.
4x: Stars in Shadow -- its AI is programmed to be FUN. Example: If a faction wants a system, it will focus on taking that system. Then usually offer peace on achieving that goal.
sRPG: Fell Seal ["must have good AI" your post makes me think you may not like it. But it's great overall.]

As of "recent", I would think that you mean from those that are on sale currently.
I strongly advice towards Divinity: Original Sin games. They are truly turn-based games and very deep. If you like real time with pause games, then there are the Pillars games.
Although you should be warned that all these are large games. We're talking about at least 100 hours each.