Tape them and then stick a tube in the tyre, pump up and leave for a day or 2.
Take the tube out and refit the tyre.
Don’t forget to overlap the tape by about a half of the wheel diameter (if the valve hole is at 12 o’clock start taping at 9 and finish at 3 after a full rotation).
As you say the sealant is there to fix holes, might be punctures but can just as well be shitty tyre walls.