The Krynn series is probably my favorite and they all have those fantasy adventure elements fans of a BG3 type game would like if they get past the old graphics. Death Knights of Krynn could almost be classified as an open world game with all the side quests.
I love these games. I was going to replay them but I'm pretty sure I had hacked versions with no level limits per game, I want to find them. I got rekt in Death Knights of Krynn as a kid, and tried replaying Champions over and over with the same party, for experience. I got so good at Champions I could start and win with a party of only knights, just resting for 1 hp a day until they would start getting cleric spells.
Death Knights is my favorite, it blew my mind w.r.t. how much content and interactivity could be in a game.
Gateway was second-best (that was before I found out how degenerate Forgotten Realms were -- it was a new, mysterious setting, the same type of sparse "storytelling" people would later praise in e.g. Dark Souls).
Dark Queen of Krynn was cockblock after cockblock, completely unfun as the plot goes, there wasn't a single thing the heroes accomplished, but the dungeons were cool. I love to hate the gong, I love to hate the pass system, I love to hate the column maze, I love to get lost underwater looking for that fucking hinge. I like that they managed to keep the game playable and strategic at high levels. The new sprites were nice, but I wish the dark wizard enemy sprite was available for PCs.
Azure Bonds was a rough start, then I learned to deal with random patrols first and was wrecking everything in sight. (Awesome novels, too.)