Safe to install vinyl plank flooring under appliances?
LVP (luxury vinyl plank) floors will not warp, crack or otherwise damage by the weight of home appliances, and being a plastic, they're waterproof and impermeable, so moisture will not affect them.  This leaves temperature as the only issue with LVP.  They also have the least thermal expansion rating of all floating floors, having a rating of 0mm of expansion (none) in normal room temperatures.

They tell you not to install any floating floors under appliances only because you are tacking them down by weight and they could possibly fail to expand in any 2D direction if you lay the planks down with appliances on both ends, so they may tent.

If you leave a standard expansion gap for the flooring to expand in at least 2 of 4 directions, you will be absolutely fine.  The flooring doesn't care which way it expands, just that it can expand.

In fact, if you do not allow direct sunlight to hit your flooring (dark flooring can go above 120 F in direct sunlight), and you never let the temperature in your house go below 50 or above 100, your LVP will never expand or contract at all in the first place.

Of any floating floor, LVP are by far the most worry-free for thermal expansion.

References:

https://www.floorstoyourhome.com/blog/which-flooring-expands-and-contracts-the-least/