You're asking for something different now again. Even a good manager could struggle with this. In one post you say just the one hour difference. In others it's about sitting, standing, breaks. All of these things are fair. But you can help everyone involved by being consistent.
Now it's structure. Do you have a special need for structure (mental health related perhaps?) If so, get GP evidence. If not, are you confusing what you'd prefer with a pregnancy or health related problem?
Get the things that aren't safe for you on your fit note: may be fit for work with the following adjustments. Then, wherever you are working, observe those limits.
Your managers don't get to override that. But they don't have to offer you exactly the hours, structure, and tasks you want either.
Your colleagues in the bakery are assuming you're lifting. Your managers say you'll be packing. Don't lift if it's against medical advice.
Your managers are behaving responsibly asking for medical advice, even if they are terrible people and bad communicators. Get the list of things you should not do. Don't do those things. Do what's safe in whatever role you're being paid to do, or if you're not well enough to do anything, return to GP and get signed off.
1:1 training in a new area is a very sensible thing for you to work on because it can presumably be adapted quite easily to your needs.
Hope the rest of your pregnancy goes well.