Nice, this looks great. The FB group called Designer's Guild was also great to me. I used it like 2 years ago when I thought of going back to programming and there were weekly (or monthly?) portfolio reviews and mentorships, also full of FAANG engineers. I just visited it for a few quick seconds this moment and looks like there's still regular portfolio reviews. It's focused on UX/design but there are plenty of devs there if I can recall correctly

Nowadays I just find my mentors at linkedin/github as it's hard to find quant/HFT devs to network with elsewhere. Also, joining system design and leetcode-style mock interviews led me to private chat groups on discord, slack, telegram, skype with software engineers/data engineers/machine learning engineers in various fields like FAANG, unicorns, and HFTs. It's literally the only valuable thing that came out from grinding useless leetcode questions for me. These mock interviews are pretty much everywhere, just google "mock interview platform" or sometimes people post about it on platforms like twitter. For example there's this group last month where we pretty much did interview prep for a month, studying the given reading material such as multithreading or MVC (or for example this is the extra work material for one of those days) and problem sets on weekdays, partnering with someone for a 30-minute mock interview, then we have live sessions at the end of the week. Such activities are a great way to build a lasting network with folks