Game crashing while playing with a friend in my world

this is like the third day that i have this when i play in my world and a friends join after some minutes my game crashes first it was only with 1 of my friend but now its with every friend (bc i played with someone else the first time it didnt crashes but the next day i played with him it began with a crash but it also crashes everytime) 

maybe important is that the world is loaded with experimental gameplay options on (but not education options)

things i tried to fix it:

-restarting my pc

-reinstalling the game (+ restarting the pc after uninstalling the game)

-updating windows to the ~lastest version (i hope its the latest Xd)

-removing all behavior and resource packs from the world

-making memory space (but i already knew this wasn't the problem bc the game normaly says it when there isn't enough memory)

but yeah none of them worked its even worse than first, first i could play for some minutes but now it crashes directly when a friend joins
also that is maybe something important is that it's like when they come near me in game that i crash faster than when they stay away from me (or i from them) but idk it just feels like that but im not sure if its really that 

my pc specs:

RAM: 8 GB
Processor: Intel(R) Core(TM) i5-3210M CPU @ 2.50GHz 2.50 GHz
(idk if this is important) build of operating system: 19043.1110
Type of system: 64 Bits and a x64 processor
idk if i forgot something but yeah i think this are the most important things 

what is also tought was that its maybe something with the connection but i never had issues in the past with playing with friends it just came out of nowhere when i played with a friend

And that was all of the information i think
thx in advance and have a great evening/noon/morning or night : p