Where to buy a local SIM card in Sharm el-Sheikh and will using one lock your phone?

One traveler clarifies that phone blocking after the first local SIM is more of an exception than the rule, based on personal testing over several months.

Bought a 10GB SIM in March, got a bonus 3GB SIM included. The main SIM kept working fine through May. The bonus SIM, inserted into a friend's phone in March, still worked fine in June (about 93-95 days later) — he just needed a new one after that.

One traveler clarifies that it's not the phone itself that gets blocked, just the specific local SIM after it expires. The usual approach is to buy a regular SIM for the trip and simply discard it after the vacation, with no issues to the device itself.

A 10-15GB SIM card was repeatedly bought right at Sharm el-Sheikh airport for $5. It was inserted into an old spare phone and used as a mobile hotspot/modem — the whole process (buying, waiting for the seller to activate it) takes about 10 minutes.