so i checked the /about and the /hospitality-and-leisure page to see the differences.
Both pages are built with a parent GB Container Block. /about has 20px margin ALL round in the container spacing /hospitality-and-leisure has 40px Top Margin in the container spacing
Personally i would remove the margins, and just add consistent Padding.
Padding keeps the spacing within the Container.
Whereas margins creates space outside of it – so you introducing gaps between elements and the browser edges… which means body background colors if different to the Container background will show through
If you’re on the tablet or mobile previews when editing the styles – the greyed out numbers are the values its inheriting from the desktop or tablet.
I would suggest fixing the Desktop spacing and first remove any Margins – delete the values or set them to 0.
Then add padding, for Desktop 40px is good, and for mobile you may want to reduce it down to 20/30px
I generally stick to 17px for the Body font for both mobile and desktop. Unless the particular font dictates a smaller or larger size.
And where possible avoid setting those sizes in the block editor for your regular text/headings instead manage them in the Theme.