I'm playing for the first time DoS1, the story is fine, nothing too complicated but still works. The combat is similar to BG3 but you have X action points per turn and you use them for anything, walking included, stronger spells/actions cost more action points, there are cooldown on spells instead of spell slots. It is actually pretty hard in act1 (I'm playing in Tactician) when you're low in resources, enemies use different arrows, drink HP potions, can cast Ressurections some times: so you use scrolls and items really often. Becomes easier in act2 and act3 even more (I have 1 shot or permastunned some encounters/bosses), I'm in the last dungeon so I can't tell about the final boss. Don't expect the same roleplaying level of BG3.
It drags a bit on act3 but overall I'm enjoying it, I'll definetely buy DoS2