Neither is a bad option, but there's plenty of room in between. Series B, C, are often still pretty collegial, and you'll still get the opportunity to know the founders. The market's really gung-ho right now, and wherever you go you should interview them as much as they interview you. Pick something that feels good and will let you
breathe. It could be really tempting to be ambitious right now and the main advice I would give you is "don't."
Don't try to make up for lost time. Don't try to prove anything. Don't make the next thing anything more than what it is: a job. Once you've rested and recuperated, and you can look back on your time at your startup and not "cringe" or feel angry, then decide whether you want to lean into the job you're at or move on and be ambitious somewhere else.
I've been a co-founder at something that felt like a "zombie startup." I walked away, gave up my entire stake in it back to the other co-founders, and washed my hands of it. It's doing fine now, and I'm fine with that. I saved myself the three or more years of pain, heartache, and panic attacks, and hopefully I gave them the breathing room they needed to get the thing off the ground. I will never see a dime of profit from it, even if it becomes a unicorn, and I'm completely fine with that.
The thing I think a lot of co-founders feel after a startup fails is a sense of "purposelessness," Burnout that manifests itself as a feeling that you're not "smart" anymore, not "creative" anymore. A blank space in your day fills itself with wondering if you could have made it work if you'd just done that one thing differently. You can't "power through" those feelings. You have to let yourself live with them until they pass over you. You have to let yourself heal, and healing takes time. Whatever job you take now should let you focus on that. It needs to be something that lets you spend some mental energy working through the regret, frustration, and ultimately the fear of facing your part in the failure of the startup.
Do the job instead of "be" the job. At least for a while. Take the time and get past all the things that will stop you from really learning from your experience. Then at the end of that, if you still feel the burn to start something again, you'll be able to put your whole self into it.