While most fire pits have substantial feet that will not sink into the basalt board of a DeckProtect, some fire pits rest a lot of weight on feet with a very small footprint.
The basalt board used in DeckProtrect is not soft, but it is also not rock hard. For example, you could press a screwdriver into the surface if you pushed hard.
The Breeo X-24 (left) is a very heavy fire pit, but even with a full load of logs, its feet will not depress the basalt. A round base fire pit (above) distributes its weight and also is not likely to press into the basalt.
A customer with a heavy chiminea that rested on 3 legs with very narrow feet was concerned that the feet were pressing into the basalt under the substantial weight.
There was an easy solution. The electric supply section of a hardware store will have galvanized steel plates that are used as covers for an electrical junction box. There are several different varieties, all priced at less than $2. Ideally it has a round "knockout" in the center that an electrician knocks out to make an opening for a fixture. The one at left is 3-5/8" wide.
To make a natural looking foot plate, the galvanized steel can be painted with Rust-oleum High Heat paint. It is essential to remove the UPC sticker and any adhesive left behind, which may require a solvent.