I've made this myself and although took some help from other scripts too..
if there are errors then please report here or add me on steam to report, i'm really wanting to make it perfect.
bind r "regen"
alias regen "sv_cheats 1;mp_waitingforplayers_cancel 1;mp_disable_respawn_times 1;ammo;health"
alias ammo "give func_regenerate;startLoop"
alias health "hurtme -9999"
alias startLoop "impulse 101;infinite"
alias infinite "sv_allow_wait_command 1;wait 33;sv_allow_wait_command 0;startLoop"
you can change the bind or health to your needs...
feedback is greatly appreciated.