Let’s start by stating that adding sealer, re-caulking, or regrouting is not a permanent solution for a shower leak. There are businesses that promote these services to remedy shower leaks, but they should only be viewed as aesthetic upgrades.
At most, they might provide a short-term fix. If you use this technique to buy some time, be aware that the failure will eventually happen again.
Complete removal of the damaged region, followed by a rebuild, is required for a shower repair to be permanently effective. This entails, at the very least, rebuilding the shower’s base, which includes the pan.
By doing this, the leak will be fixed without having to spend money on remodeling the entire shower. Flood testing of the pan is a good idea after the waterproofing has been repaired.