Griff, this is just my opinion and I don't know your situation, if you like to cook, or what you've already tried, so ignore any and everything I am going to write if it doesn't pertain to you, lol.
Before I offer it, though, let me digress and say that there are a few of us here who are all gluten free (at least two because of celiac). If you ever want help with baking or cooking, just post. We'll be glad to help.
Now, on to pizza and sauce. My husband is Italian and has celiac. I had to figure out pizza and quickly! But, canned and jarred sauces didn't work well for us - often too salty, often with off tastes.
Option 1: IF you don't mind doing some cooking, you can make and freeze a pizza sauce that is heavenly and ready anytime you want pizza. Now, you may prefer the convenience of jarred/canned, so ignore. BUT, if you don't mind a bit of work on a Sunday, you can have LOTs of sauce ready whenever you want it.
I make a very simple red sauce - as his mother leaned in Calabria, Italy: Italian tomatoes, garlic, olive oil, part of a fennel bulb cut into largish pieces (I remove after cooking), salt, lots of basil (whole leaves - I remove after it's done), a bit of sugar (his mom uses a LOT, but I prefer it less sweet), and some tomato paste. That's it. She removes the seeds, I do not. We both put canned tomatoes (some are MUCH better than others - but it depends on what you're looking for in taste) through the food processor, cook the garlic in a couple tablespoons of oil just until fragrant, then added the remaining ingredients, and cook down. My brother-in-law does the same but adds onions and peppers.
Before freezing in individual containers, I take a couple of containers, add some more tomato paste, and I've got delicious fresh-tasting sauce. I freeze it, just as I do the sauce. When I want pizza (or pasta), I just remove the amount I want and thaw in the microwave. Always on hand, always fresh and delicious. I do add extra spices to the top of the sauce most of the time, but tend not to freeze it with them.
Option 2: IF there is a jarred pasta sauce you like (and many if not most are GF), you can turn it into pizza sauce in one minute. Just open a can of tomato paste and add a couple of tablespoons of it. It will thicken it so it's not too thin. If you want, add a few more spices. If you have extra paste, put "plops" of it on waxed paper and freeze; when frozen solid, throw into a zip plastic bag and remove when needed.
Option 3: Not related to sauce, but if you want/need a few pizza dough recipes, let us know. Veloute makes one an exceptionally easy way that she makes as a very thin cracker crust but can be a bit thicker and chewy if you don't cook it as long. I have two different recipes that aren't too much work, but it's harder than what Veloute does. One can be either crispy-cracker like or chewy like Veloute's; the other one is like a NY pizza crust - completely fold-able, thin but not cracker like, and a bit chewy. I also have a couple thick crust recipes that are good, but we don't prefer that so I don't make them often.