I’m wondering what you’re trying to achieve? If you don’t want a prime tower, just disable it in the slicer.
Purging into the bucket won’t really help, because the backpressure in the nozzle while purging is different from actual printing. That’s the main reason for the prime tower: To prime the nozzle for printing conditions.
I completely agree that mixed prime towers from PETG and PLA are problematic, but I think a much better solution would be to just have separate towers, as was already requested here.