There are heaps of threads in the archive, just a bit tricky to find them 😁
If you are dealing with a PCI system, it's likely quite modern (in retro terms) with a Pentium 3/4 or an AMD Athlon...
So I would use this machine to focus on the later DOS games that used General Midi for music and Sound Blaster 16 for speech and sound effects. These modern games are highly compatible with PCI sound cards.
A cheap candidate is the Ensoniq AudioPCI and it's Creative siblings. IMO excellent General Midi and high quality digital audio (even SPDIF if you want) for a very low price. Downside is that it doesn't work with all games because it needs EMS memory.
The Aureal Vortex 2 card is also very good. But it doesn't come with onboard Midi, so you need to purchase a Midi daughterboard.
For games that use FM there is simply no way around building a dedicated machine with ISA slots. It's as simple as that...
All the modern games support Midi. Either through MT-32 or General Midi. It's really only the early games that have no Midi support at all.