In order for the tubeless rim to hold the air even without a tube, you need the right rim tape in addition to good valves and special sealant. DT Swiss has a version for this on the market, with which I have had good experiences across the board. It sticks well and is available in a variety of widths, so you don't have to wrap multiple layers just to cover the entire inside width of the rim. Incidentally, this rim tape also works great with a tube. Once mounted, it always stays in place, unlike without glue. I always recommend a few millimeters more tape than the rim bed. So about 21 tape in 19 internal widths. This seals better against air loss. When installing latex tubes , I even go a little wider and use 21 mm rims on 17 mm rims. You can read about how and why this is good here on my blog .
In addition to all fast bikes for the road, I also use the DT Swiss rim tape in a wider version on my gravel and mountain bikes. Also important here: pay attention to a grease-free rim bed and start at the valve hole. Then simply wrap it around the center and then stick the tape on with a few centimeters of overlap and press on well. If the tire and rim have too much play and don't want to seal at all, another layer usually helps to get the fit tighter. Tubeless is sometimes still a bit tricky, but it's no longer rocket science!
There are three widths here: 21, 25 and 27 millimeters.
The price is for ten meters on the roll.