There's not really anything specifically to improve connective tissue except make sure you have nutrient and you rest. We don't even really know why muscles strengthen. The explanation you hear of "micro tears something something doms grow back thicker" is demonstrably false, as far as I can tell it's like "umm hormone bullshit inflammatory markers go?". Part of strength is also neuronal signalling improvements hence "greasing the groove" stuff so it's not even entirely clear how strength specifically builds. Bodies are fun!

Tendons and ligaments are poorly vascularised, like if you've ever seen the insides of a living animal (like watching surgery videos or witnessing a significant injury whatever) you'll notice they're kinda pale and don't bleed much. Consequently they're not very active metabolically and just take ages to grow. Snapping them is so bad because it takes months to heal and slow healing = bad healing.

So loading up too fast, or skipping rest (something I would know nothing about having flawless mental health and not holding my life together with running) will accumulate damage until they fail.

I get the self consciousness at gyms but honestly giant gym bros are usually really nice and helpful. Think of it like they're muscle hobbiests. It takes so much work and focus to get there that they have to be pretty passionate and most people genuinely enjoy others being interested in their hobbies and want to help beginners.