As has always been the case with terrestrial TV transmissions, Freeview signals are broadcast at power levels which assume that viewers will be using good quality
outdoor aerials. i.e. ever since TV transmissions first started in the UK, it has never been the intention of broadcast engineers to transmit signals which can be received by indoor aerials. (Indeed, they deliberately keep signal strengths to a certain maximum level to avoid interference with neighbouring transmitters).
So your proposed method of resolving your current problem (i.e.using an indoor aerial) can't be guaranteed to work. If you happen to live very close to a transmitter though it's possible that you could get an indor aerial to provide an adequate signal. (It certainly wouldn't work around here though. Most people find that they need multi-element outdoor aerials, at the tops of very tall poles, to get a decent signal).
If a loft aerial would be possible in your situation then a decent tri-fold aerial, such as this one
https://tinyurl.com/y6uhdllv
(possibly with a signal booster as well) might well do the job. However, unless you live within 5 miles or so from a transmitter, most 'set-top' aerial simply aren't up to the job.