RTX 5060Ti 16GB or RTX 3080 20GB?

I would like to dedicate a budget of about 500 euros to upgrade my workstation and run inference on the qwen 3.6 27b and gemma 4 31b models. I currently have an RTX 5060Ti 16GB. What do you recommend I buy: an RTX 3080 20GB or a new RTX 5060Ti? They are both around 550 euros. Is it worth having 4GB VRAM to get an older, modded model? Currently using llama.cpp but considering if possible vllm or sglang. P. S. Sorry if my post seems low effort, but I am really undecided, and searching through the posts on this subreddit I only find old posts and they don't directly compare the two GPUs.