Most of that is nonsense. Historic England take a pretty pragmatic view on keeping listed buildings in use because in the long term that is the only thing that guarantees their survival. They've written some pretty progressive guidance on how thye can be modernised and even how they can be made more environmentally friendly. How diffcult they may be to sell deends a lot on the property. Listing doesn't seem to cause too many problems in the upper end of the market, but don't expect to be able to put Everest windows in a two-bed terrace in Saltaire.Run away.
Planning consent is one thing, but the Building Control people may not approve the only things the Historic England will approve, and you are stuck in the middle. As Building standards evolve with time and the influence of people like Greta you may find that the changes may have been OK standards wise at the time, but they no longer meet the current standards. This why searches look for work that has not been issued a completion certificate, it can get very expensive even before the history buffs descend. Modifications like Crittall windows which were not original are much liked by some conservation officers, and you are stuck with draughty single glazing.
Even if you got away with it now, unless fully resolved you may have issues when if comes time to sell.