If you are courageous 😋 there is also a preversion of LLVM port (with partial C++ support)
llvm-mos.org/wiki/Welcome
and (my beloved language) a Pascal compiler (and IDE) too 😅
github.com/t-edson/P65Pas

for flashing, you can emulate a 27xxx EEprom via a simple STM32 or RP2040 or ESP32 to speedup process, or you can use flash memories pin to pin compatible with 27xx and progammable via TL866II Plus programmer
AM29F010 / AM29F040 / SST39SF010 / SST39SF040
W27C512 / W29C010 / AT29C010

The cc65 cross-compiler suite github.com/cc65/cc65
You can also use the port of VBCC compiler that have the 6502 backend now sun.hasenbraten.de/vbcc/
for emulation and dbg
skilldrick.github.io/easy6502/
github.com/mnaberez/py65
for flashing I use TL866II Plus programmer,

Keep it alive, you can eat it later, it's a good protein reserve 😂

Finished printing 4 units