Thanks for posting, somehow I missed @frangdelsolar response so this reply is for both of your questions:
Short & Simple.. ok yea – it worked, but was very limited and buggy
We then hired 5 different programmers off upwork that swore they could make a custom calendar plugin better
Then we looked into custom buddypress development costs. Wow – you could have built anything from scratch for those prices.
The particular project I was the project manager but the funding ran out, but I sank a year of my life into it so I do still remember parts of that dilemma and the solutions that were in the works – if you wish to more – send me a msg
I do have 20 years experience in the business and have a good idea of which plugins work well together and which ones waste your time. If you let me know what your site is about and how you need a calendar to be integrated, I’ll see if I can point you in the right direction