I have had the same in the past, where damp gets into the cables and it freezes so the handbrake doesn’t release and feels like you are describing. Maybe try leaving it in gear without the handbrake on to see if this improves?
Clutch doesn't appear to be slipping, although it's well on its way out. DMF has been chattering away since I purchased it, but doesn't appear to be any changes relating to the revs. Just seems boggish and slow on cold start
Is it revving up as normal but not moving the car (suggesting additional drag, perhaps a stuck parking brake), or revving up too little (suggesting the engine is down on power) or too much (suggesting the transmission is not transmitting)?
