Sounds like you are backwards from where I was; I wanted to start my marketing consultancy, but needed to pay the rent until I built up my roster of clients. So I became a Ghost Tour Guide at night in Pike Place Market in Seattle. This allowed me to work on by business during the day - meet with clients, write, promote, etc. - and make enough money at night to keep me in Ramen and rent. The better I did, the bigger the tips I got! So you have the "night job" sorted out. Now you need to figure out what fills in the other time, and is flexible, so when tour season picks up again you can focus on that, and put the main gig on life support. Which is basically the point of the "gig economy" like Uber/Lyft, Mechanical Turk, DoorDash, pizza delivery, and all that crap. But I don't think that is the right direction for someone like you... I like the Volunteering thing. It gets you involved with a group that needs help, and could possibly lead to something full-time in that particular area of work. What about merging your vlogging and your tours? Do short vlogs of particular parts of your tours... something that people can watch to not only learn about your city when they are coming to visit, but also to learn about YOU and your PRODUCT: the tours! You know vlogging. You are good on camera. You know your tours. Now merge the two together! I had people take my tours multiple times, simply because they enjoyed the experience. So you aren't limiting the pool of people who will attend your summer tours; instead, you are expanding your market to people who may never take your tours, or who aren't capable (wheelchair, physical infirmity, etc.), and appealing to a whole new market of people who like history, travel blogs, etc. I'd watch them. And I wouldn't skip the ads on YouTube either, just to make sure you got the monetization! :-)
My vlogs were already on a bit of a backburner, but then my camera got stolen in Eindhoven and i lost half my african safari footage. And I can't really afford to buy new gear right now. It was a fun adventure and I learned a lot, but it wasn't really going anywhere anyway so I think it's time to move on to other things.
Well that sucks ass. But it is something you can do instead of "feeling unproductive and lazing around on the couch self-loathingly", - you already have the skills learned/refined, - even a cell phone can be all the equipment you need at first, - and it has both a physical bricks-and-mortar aspect and a virtual/viral aspect to the business. That gives you more coverage/reality than your usual YouTuber, and a target market (visitors to Montreal), that is easy to target and market to. It's an option. But I also understand when I am just DONE with something, and want to leave it behind. I get it.