The company HobbyPC sell a band pass filter for 2M, 1.25M or 70cm for 20$ each that can handle 20W … I have some and they are more than adequate … I use a low pass filter after my VHF amp because it outputs 100W with roughly 10mW drive (single block amp with bias control for SSB)
https://hobbypcb.com/products/uhf-vhf-radio/144mhz-band-pass-filter