It's likely not motors throwing warnings, but drivers. In either case the best way to solve it, is lowering the current.
In normal scenarios motors should be warm to the touch during operation, but not hot enough to burn your fingers. You should only up the current and install radiators on motors if you are doing it on purpose (e.g. "overclocking" the print speed), which in your case isn't needed at least until you upgrade your extruder and install high-flow hotend.
On your old board with stock Marlin - you need to do it the old-school way with multimeter and a tiny screwdriver. Adjust it to no more than 1.2A running current.
Once you upgrade to Klipper (and assuming your new board runs TMC drivers in UART mode) you can change that in
printer.cfg.
Too expensive for what it is. Heck, you can buy a whole printer for that price. While all-metal sounds cool and all, and machined aluminium looks intimidating and reliable, it's still a single-gear piece of excrement. Even a plastic BMG clone for $3 will perform better. Heck, even your stock extruder is better(cause it's basically a BMG clone). I'd rather get an all-metal BMG variant from Aliexpress, or even go as far as doing this:
I remixed the factory models to mount the Voron Stealthburner hotend and Clockwork2 extruder. As well relocated probe | Download free 3D printable STL models
www.printables.com
Or design your own mounting brackets for something like Orbiter extruder or one of the newer planetary-geared compact extruders. Creality has a decent one, though it's still heavier than an all-metal orbiter.
This will make your toolhead much lighter, and will give you a little boost in print speed as well.