Anyone know anything about disc brakes?

Facing a dilemma

Commuter bike is a flat bar Pompetamine with bb7s 160mm rotors I have been happy with these (take a little while to set up but then ok).

Nicer bike Genesis Vapour Disc (tiagra 10 speed) with hayes cx expert 160mm rotors, went to put mudguards on this today (after a little while in the shed due to winter and no mudguards) to discover rear brake is super stiff, not sure if lever, caliper or cables.

Going to drop Genesis into the local shop to see if they can diagnose/fix (and put mudguards on at the same time). I have found the hayes ok while they have been working (a couple of thousand km) but not yet had to do anything with them/even change pads and understand from reviews they are not 'favoured' as such I had thought about changing them anyway.

Hopefully there will be an easy fix; if not and I have to spend money having trouble deciding which of the following options is the best way to resolve...

Option 1: I believe the forum favoured calipers that would work with my levers would be a direct swap for the hayes would be TRP Spyre (~50 quid a caliper, thought to be better than the bb7) or HY/RD (~100 quid a caliper) if I want to pay a little more?

Option 2: would be to move the bb7 calipers (which have had a fair bit of use) to the Genesis and get some shimano mtb hydraulic disc brakes for the commuter ~50 quid an end for deore 615 (this seems an ok option?)

Option 3: Go full (shimano) hydraulic on the Genesis, but am I right in saying that as I currently have a 10 speed set up the most cost effective way to do this would be to buy a full groupset ie this 105 one for 500 quid and then sell/parts bin the 10 speed stuff, need to check my hubs are ok for 11 speed if going for this option.

Have I missed anything, opinions informed/otherwise as to the best option welcomed!