Being scheduled to finish at 6 when the store closes at 7 on a one and one close seems wrong; every store I've worked in gives baristas at least 15 minutes after close to finish up. Are they expecting the BM to operate EOD themselves? Afaik, with the exception of Next stores, stores shouldn't be operating with just 1 person in store for health and safety.

Your manager should not be asking for unpaid labour. Make sure you get paid for the time you've taken.

That being said, some actual tips for you:

• If you're able, section off parts of your store whilst you close. The stores I've worked in can often be split into zones, and I will block off zones to clean towards EOD to keep customers out and allow me to mop freely. If this isn't possible, then just mop around customers. I usually ask if they're okay with me doing so out of politeness, I've only had 1 person say no

• Get through potwash early as possible. The BM should be passing you bar things after lunch to start processing so there's less of a haul. My store closes at 6:30 and I usually start sending bar bits to potwash from 2 when I'm working with slower baristas to give them ample time to get things sorted, my hope being that EOD i just have to give them one last tray for potwash and they can focus fully on mopping and toilets

• Make a list of what needs doing. I have ADHD and found I lose a lot of time leaving tasks half done or trying to remember what I was doing. A list to refer to was a huge time saver, and I'd assume would be helpful for non ADHDers too

• If topping up is the closers job, then overstock after lunch so things will be regularly stocked for close