When you bake with plain flour you've got to get a feel for the hydration and usually reign it back a few percent. If I mix in 25% plain flour with bread in the bread machine then the bread rises higher. I really like it like that but somebody I know complains they've got to turn the bread over in the toaster and that's the last thing they want to be doing in the morning when smaller things are squealing and knives are freeling available.
The bread maker recipe is
400g flour
280g water (70% hydration)
glug of oil or a bit of lard, salt, sometimes sugar for a bit of colour, 5g of yeast.
Stretching and tucking for tension is more important with the plain flour and you need something to use as a banneton or let it rise in a tin. I use a saucepan with a lid lined with a silicone sheet and keep the lid on for 20 minutes to keep the steam in.
This was the the test where I backed it down to 65% hydration but I'd start a little lower and see if it'll take it without getting too slack.
https://www.thehomebrewforum.co.uk/threads/bread-****.84618/post-879412
And DON'T add more flour while kneading if it's at a hydration you know works. You'll think it's fully kneaded when it's not. Lots of my problems while getting better was from under kneading.