Resizing the swap partition in Proxmox Virtual Environment is a quick process. No reboot is needed. This method was tested on PVE 8.4.1.

# swapoff -a

8G stands for 8 GiB of swap. Adjust as needed / wanted.

# lvresize -L 8G /dev/pve/swap
# mkswap /dev/pve/swap
# swapon /dev/pve/swap