How big is the bank? There are some RAM expansions to consider. You can find options at https://amigakit.com and also check out second-hand stuff at https://amibay.com. Most of the newer RAM expansions do not have clocks, but if you are only playing games and demos you have no concern with the clock. Also, most games of the era for the 500 work just fine with the 512k RAM of the most basic Amiga 500. The Amiga 500+ has 1MB of ChipRAM which can be upgraded to 2MB (1MB on non-Plus 500s.)
You either need a monitor which can handle 15kHz video or get something to up the scan rate. Scan-doublers have become rare commodities but not impossible to catch. There are external options like the Gonbes, RetroTink, etc. which will run anywhere from $20 to around $200. There were some internal scan-doubler/flicker-fixers made in the day which pop up from time-to-time, or a modern option is the Invidison ECS (seems to be available from iComp.)
Kickstart 1.3 is the best for games of the era. Most likely, this is what your 500 already has.
I believe there are some modern IDE interfaces which sit in the CPU socket. ISTR one or two which also offer RAM expansion, as well as some full accelerators. If you are just playing games from ADF on the Gotek or real floppy disks, then a hard drive is minimally useful. Most of the games do not install to hard drive.
If you want to use the system with WHDLoad, which allows the installation of numerous games to hard drive, then you will want to expand the system: KS3.1.4 and AmigaOS 3.1.4 (available from Hyperion,) ChipRAM* and CPU RAM expansion, as well as at least a 68030 accelerator. The Supra SCSI will likely work in this configuration, but keeping it means SCSI devices like hard drives old enough to drive or SD2SCSI, SCSI-to-IDE-CF, etc.
I have been out of the 500 stuff for a long time -- my two 500+ are fitted with an original ACA500 and a Vampire. I just took a quick look, the ACA500+ is currently selling. It is not a 68030, but the boosted speed of the 68000 appears to be perfectly adequate.
Good luck, and welcome to the Light Side of the Force
* ChipRAM expansion is limited in-board to 1MB with a non-Plus 500, or 2MB with a 500+. Non-Plus 500s can be upgraded to 2MB with a MegAChip or clone, the former which are ridiculously expensive these days when they pop up.