What are your tips for healthy living for WFH alone/single people?

Move out

For me it all starts with sport. Start small with it, then you start to pay more attention on what you eat, decide to buy more books etc. Find that one thing for you, could be different thing. The moral of the story, start small :) Hope you find your way, cheers!

If I was still single and without kids, I would be doing a morning run, taking an afternoon power nap, and going for the occasional coffee run. Now I mostly lift weights (kids).

Find an IRL community - women in product, women who code, startup founders, indie hackers, mountain climbers etc, whatever resonates with you, and participate. It will be awkward at first but then you will find friends and new acquaintances and you will start looking forward to the events. The only way to break out of monotonous WFH loneliness is to find other ways of human interaction.

Create a calendar of schedules and strictly follow them. That way, you won't be tempted to just lazy around in the house, and I tell you, there are many temptations, after all, you are in your comfort zone. Good luck!