An ordinary 100mm bathroom fan shifts around 80 cubic metres of air an hour, and is adequate for a room with a bath. Soler & Palau are very good, and quiet, so you will hardly hear them, and not at all when the door is closed. There are some special cheap ones that builders use at around 60 cu.m/h that are noisy and wear out fast.
If you like steamy showers, I think you need around 250 cu.m/hr, and this can be done quite eaily if you have access above the bathroom ceiling for a duct. The fan unit is too big to put on the wall.
You will need a fan that comes on with the light switch and has a run-on timer. Humidity-sensing versions are available but are not much good.
If you can't fit a duct, you can fit a larger size of fan, which needs a bigger hole in the wall.
For electrical regulations, most fans have to be at least 2250mm above floor level if they are directly above a fixed bath or shower tray; or the shower area in a wetroom. A fan in the loft is not in the bathroom so this does not apply.
This is an example of a good-quality inline ducted fan. I have never used a brand as quiet as S&P. They make larger/smaller/quiter ones as well.
][https://www.tlc-direct.co.uk/Products/ADAV100.html This]] is an example of a cheaper brand. I have used them and they are similar, but not quite as good. Not as powerful, not as quiet, not as well made
There are other brands that are even cheaper.
Rigid tubular duct is much better than the flexible hose. You can tilt it so any condensation runs outside, and it does not accumulate fluff and water so much. It takes more effort to cut and fit the rigid duct.