I guess it depends on what you do with the device. I have not ran into any performance issues with either my mini 6 or iPad Pro 11 (2018). For me performance on both of these are fine. My kids have a Chromebook that I bought them for Christmas. I would call that a tolerable experience.
Back to the OP it depends on what you want to do with the iPad and how long you want to keep it for. I think it will run ok and get updates for the next 2-3 years. In the OP’s case they already have a device with the same chip so they have an idea of the performance. However going from the 11 inch the the 12.9 inch with the same chip is more of a side step imo. If I was going to go through the hassle of charging my iPad I would want an actual upgrade not a side grade.
As for whether it’s worth buying off the bat in 2023. It really depends on budget and how much it’s gonna cost. I personally wouldn’t want to pay more than £300-400 for an A12Z device in 2023. I paid £700 for mine in 2020, so I would expect to pay considerably less 3 years down the line.
The price of the 12.9" is not the same as the 11". A12X devices are still selling for $400-500 with 256GB storage. A12Z probably for more, although not everyone knows about the difference. And I am not even talking about Apple refurbished, which is basically new.
As for "performance", this is a very subjective thing based on how each person uses the device. Anything A12X or later is still blazing fast in terms of CPU, but RAM may bother some (especially those who use Safari) and not others.
Personally, having both the M1 and the 2018, I started splitting the use. Safari on the M1 and other apps (streaming, notes etc.) on the 2018 and they both work great. And I have to worry less about battery life
