To add to this post- I made the jump from an i9 to an M4 MacBook and foolishly expected to do what I've always done, simply move the .pvm file and away I go. But sadly not- I was completely unaware of the implications of the change to ARM from X86.
I managed to get everything working on a new install of Win 11 (once installed) apart from TIA V18. Pretty much every driver needed to be manually downloaded from the manufacturer (FTDI, USB GbE, etc) or via windows update. The only thing I couldn't resolve was TIA, as soon as I opened a project and wanted to open a block, it crashed. I eventually download the most current version (at this time V18 SP5) and it was straight in! Connection to a device was then a headache and required the IP address within the parallels config to be changed to the correct range, and then the adaptor itself, as per normal. After that I was able to ping the device but it couldn't see it in the connection window- changing the type of device it is searching to "show all devices with the same address" and it was away and working- this seems to be consistent for everything I've now connected to.
The big difference with the ARM chip after my first week in action- laptop barely warms up, slightly faster operation in TIA (and significantly faster everywhere else) and the big one, battery life. More than a day on Site and over 40% battery remaining- I'd be lucky to get 3 hours beforehand and red hot and noisy laptop. Best part of a weekend spent setting it up, finding old installation files for all my softwares, transferring saved files and then the TIA headache, but it's working and has been well worth the effort.
Also a word to the wise that don't want to use migration assistant- I couldn't transfer between Macs, having set my old one to restart in target disk mode after having disabled FileVault, using a thunderbolt cable. I needed to use 2x ethernet adaptors and a cat 6, then in Mac settings enable "file sharing" and this moved some massive files/ folders in minutes- rather than via an external drive.
Hope this helps someone else as it was a lot of wasted time my end!