Usually I've typed up the raw text in a wordprocesser (Sublime Text, Microsoft Word). To put it all together, I've used Microsoft Publisher in the past; this time I started working in Publisher, but struggled to make my game look pretty. I've switch to Canva which has been a bit laggy (probably due to the size of my document - I've also used Canva to create social media content that is just one page and no lag there) but I love its design power and I'm much happier with how my final product is turning out.
Noting down Inkscape to look into later, thanks!