if You don't think an m1 iPad is needed, then the buy the iPad Air, or the iPad. that is for you.
I find it funny how many people say this, I bought the m1 iPad because I needed the power. I use it to stitch photos on location and it is perfect for that. all previous iPads took too long and were slower than my 8 core MacBook Pro, the m1 is now just as fast making it useable for what I need to do.
If you want the 12.9", the iPad Air isn't going to cut it, neither will the base iPad. OTOH the 3rd and 4th Gen 12.9" iPads are available from the Apple refurb store and they might. An M1 12.9" will 5G and 1TB costs $2000 and that is before you add the keyboard case and maybe pencil. The 4th gen refurb is $1,299 and the almost identical 3rd gen is $1,179.
The older iPads are lacking in the RAM dept of course and they don't have the TB port but the cost saving is huge.