I have a Remington with a platen that has had every single letter space indented. I assume the prior owner(s) were hitting the keys hard. I have tried to mitigate the hardness and the extra pressure needed to put ink on the page by adding extra sheets of paper behind my first.
That’s IMO the principal problem with typewriter restoration. But to restore the platen seems possible without exotic tools, if you have time and patience.
There’s a tutorial on YouTube, and it looks almost easy when he does it… but I doubt it is that easy in real life. The seasoned collector from the YouTube channel Just My Typewriter had troubles with feed rollers in one of her videos: if she had troubles, I fear to try, but I’m not very competent.
The other option is to send the platen to a professional. But that will cost you quite a lot, I think. I heard that JJ Short was good.
Me, I generally just accept the hardness. The trick you described to use two sheets of paper seems enough.