yeah I played bg3 with controller split screen with my wife the entire playthrough. Normally, I would've strongly preferred KB+M for such a game. We definitely got used to it after several hours.

I'm not sure if I can recall any tips other than just keep at it and it'll eventually become muscle memory. I don't think it's as good as KB+M but it wasn't something that was bugging me once we got significantly into the game. YMMV.

As a Steam Deck player (who mostly streams from my desktop at this point but still pretty much exclusively games with controller inputs nowadays), I got frustrated with a lot of the "automatic" management of the radial menus. Quite often, when the game adds a new ability to the radial menus, it completely rearranges them, and for some reason it really likes to automatically add things even if you manually remove them, so it becomes very unwieldly especially for spellcasters at higher levels. My frustration reached the point where I realized I either needed this problem solved or I just wouldn't be able to play anymore, which was disappointing for me given how much I've enjoyed it, so I decided to bit the bullet and start developing a mod to try to impose some semblance of order on the radial menus myself. Unfortunately it relies heavily on the Script Extender, which isn't available on consoles (and also doesn't work on the Steam Deck native version, since it's provided as a DLL that gets loaded by the game and presumably would require a non-trivial amount of effort to port to a native Linux shared library), but so far I've implemented a number of specific settings (which can each individually be enabled or disabled) around automatically preventing changes to the radial menus in certain certain circumstances and clearing them in certain other ones (e.g. for new games or when changing ca character's class). Most recently, I added a way to define a custom keybinding to manually lock the radial menus for the currently controlled character until manually toggled off by hitting the keybinding again (which currently doesn't persist past a reload, but I'm fairly close to being done integrating it with a Script Extender feature to preserve arbitrary data alongside save files so that it's possible to save them so that they get restored to the same state they were when a given save was made. Given the reception when I starting publishing this, there seem to be a small but passionate set of players with the same frustrations as me, which helped motivate me to spend the time to keep working on it.

To me, the modding ecosystem is probably one of the two most important things about this game (the other being that Larian seems to be pretty awesome as far as studios go nowadays, with their CEO taking a firm stance against "crunch" to get games out and in favor of the model of offline games that don't require paid DLC or microtransactions, as well as their continued support of the modding ecosystem itself). Long before I ever considered writing any mods myself, I started referring to BG3 as similar to Skyrim in that the mods will likely keep things fresh long after new official content stops coming out. I still think this is true, but I also keep being surprised just how much work they're continuing to put into the game even with new content presumably finally having come to an end.

I got used to it after a few hours. M&K is probably the better experience overall, sure.

You can just plug a keyboard and mouse into the Deck if you prefer that.

tbh, I've thought of doing this, but it seems kind of outlandish given that I primarily play my Steam Deck in bed. I'd rather just take my laptop with me.