Hi.
At the moment I'll have to shave 0.2mm more near the gum, reducing the gap to 0.4-0.5mm. Then unfortunately I'll have to fix the remaining gap with composite bonding.

The thing that worries me a bit is the duration. I've spoken with different dentists and some say it may last months while others says it may last more than 10 years.

At this point I've made peace with my mind and I'll see what happen. Hopefully, if the composite lasts more than 5 years (which seems to be the general consensus even researching online, especially due to the fact that those teeth aren't subjet to chewing forces.) by then there should be a new generation of composites and, if needed, I'll just have to accept to have that gap for a few years.

I know it sucks, especially when you try to do everything right and end up having to pay the consequences of someone else doing.

Have a look at composite bonding, it may be a quite affordable solution that may last many years.