I have owned 7 glocks, still own 4. Of my go to pistols, g17 at the night stand with night sights and crimson trace laser grips, g21 is my car gun, with a lasermax guide rod, g34 is my competition gun, and g20 my hunting pistol. None of the above is my carry pistol due to the width of the slides, some physiques can carry one well, mine does not, and my involvement with the public, in the positions I have to get in, would reveal any waistband carry regardless of make. So I front pocket carry a J frame Smith, to fight to my Glocks or rifle.
All of the above have 3.5 lb trigger connectors, don't let anyone tell you not to put them in your pistol, the true trigger weight is more like 4-5 lbs, but much superior to the 5lb or 8lb connectors which you can add 1 - 2 lbs to the stated trigger pull. Now my G34 has a much modified trigger and is honestly about 2.5 lbs with no creep or overtravel, I will not reveal how that is achieved as it must be done with some strong warnings, and someone who knows whats being done and why.
I've been a Glock armorer since 1991, that is a lot like being a Maytag repairman, I do 5% repairs and 95% modifications, sights, trigger jobs, etc...
In that time I have seen exactly 2 frame rail inserts break, it did not stop the gun, but was uncovered in routine cleaning.
I have seen guide rod breakage and the same thing, pistol running fine, found when the pistol was disassembled.
I have seen 3 Sig 226's with cracked frames, right above the slide release hole.
A Glock is a lot like a 4lb ballpeen hammer, not the right tool for everything, but I doubt your gonna break it, and when you do use it, it's gonna get the job done.
As for the sights, you can get excellent replacements, My pistols have the Warren sights which I do like for competition , Mepro light adjustables on my G21 which I like because it has a very tall front sight, Bomars on the G20 for hunting and accurate adjustability, and Trijicon for the bedside gun.
Enjoy your 4lb hammer.