My recommendation is to just stop and not bother anymore. 😀 Like you, I also tried many 6xxx video cards on Win98, including 6600GT, 6800, 6800GT and I can assure you, there is no driver in the world that will make these cards work properly on this OS (even if you somehow manage to install the driver eventually). Some games will run and work OK, but most of them won't: there will be severe texture corruption, freezes, BSODs, and many other issues. A GeForce FX is as far as you want to go for Win 98.

If anyone else has this Geforce 6200 LE 256mb card it will work in 98se without any problems but I think it has to do with which motherboard it goes in as I was using it in an old GA-6BXC with ISA and PCI and now it's in an Asus P4S800-MX SE with a Pentium 4 3GHz CPU all I had to do was add the lines to the Nvaml.inf and run setup.exe, the Nvaml.inf is in the 81.98 version I downloaded from Phils computer lab so it might be different to the 81.98 from Nvidia as googling said the Nvidia 81.98 file is called NVAGP.inf. I can run games that are card speed sensitive with the geforce 6200 LE and there are no glitches as some of the other cards I've tested with made games unplayable, the Asus P4S800-MX SE is compatible with 98se and has drivers for it on the Asus website

Resource conflict can't be solved with .inf driver hacks. Disable stuff you don't need in BIOS, pull any PCI cards you put in, and hope this will solve it. If it doesn't, go to PCI resource settings in your BIOS and try to free/"lock" what GPU needs to function.
Alternative is to forcefully Disable conflicting devices in Windows device manager.
Also, installing Windows in non-ACPI mode might have helped with this conflict, but I'm not 100% sure.