I fully converted to Intel Mac in 2020 when I got this MP from eBay for around $200. Was running Mojave up until 2024.
OCLP (OpenCore Legacy Patcher) is what allowed me to install Sonoma. I could upgrade to Sequoia, but I see no advantage to that at the moment. Tahoe is out though as the devs haven't cracked compatibility with older hardware yet.
It is my primary desktop Mac. Graphic design, word processing, internet browsing (I use Vivaldi mainly, latest version), and anything else I need it for. Email I generally handle with my iPhone.
Click the link in my signature that says '10 displays' if you want to see my MP (under the desk).
Don't ask that question here. The forum is filled with Apple fans who simply like to have the best stuff that they can get, even if they don't need it.
If your 2021 iMac is based on the Apple M1 chip, you will be fine for a long time. But if this is an Intel-based computer, you might start thinking about looking around for a replacement.
The need to do something with the printer is likely a fault of the driver software for your printer and might happen even on a newer Mac.
It is not uncommon for some printer brands/models to abandon users by not releasing new drivers with OS updates. If this is the case, you would want to look at the printer first. A new Mac could actually make it worse. They benefit...by users buying new printers more often.
What printer model? What is the problem you see with OS updates?
My primary "serious work" laptop is a 2019 8-core Intel Core i9 16" MacBook Pro with Radeon Pro 5500M graphics. Currently on Tahoe, where it will remain.
For "light use", I use either a 2015 12" Retina MacBook with dual core 1.1 GHz Intel Core M with Intel HD Graphics running Big Sur; or a 2008 Aluminum MacBook 2.4 GHz Core 2 Duo with Nvidia 9400GT graphics running Ventura thanks to OpenCore Legacy Patcher. (That one is also set to dual boot Kali Linux.)