Is there a way to download an older version that doesn't require the M1 chip?
This assumes an older version exists and the developer hasn't crippled it in some way. Someone might have an old x86-64 version of the installer somewhere but it might require a serial number, need to "phone home" for activation, or something to make it work. If the developer revokes permission for the app to run then getting it to run will not be easy.
As other answers point out Apple will certainly do what they can to assure people with Intel based Macs can run anything in the App Store for years to come but it's up to the developer to want to create an Intel compatible app and make it available.
It's possible that someone, at some point, will make an M1 Mac emulator for Intel Macs to allow the running of newer apps on older Macs. The M1 is based off ARM and there are 64 bit ARM emulators available now, with QEMU as one example, that could be updated and expanded to run macOS for M1 on macOS for Intel. I believe this to be nearly inevitable, just not likely to happen tomorrow.