How to protect 15-amp circuit from UPS with 20/30-amp draw

I managed to pick up a great deal on a CyberPower OR2200LCDRT2U UPS. Unfortunately this box has a NEMA L5-30P input plug (NOT a L5-20P as specified on the product page). In the location I'm trying to set this up, I only have a 15-amp circuit with a 15-amp breaker. Further, it's basically on the opposite side of the house from the breaker, so I suspect that running a dedicated 30-amp line would be prohibitively expensive.

Now I have found that there are adapters you can buy like this or this but I'm not sure if I am creating a fire hazard by using one. Will the breaker trip immediately if my rack draws more than 15 amps of power? Am I at risk of creating arcing by doing this?

I don't expect to be drawing anywhere near the maximum capacity of this system. Just looking to figure out if I'm out of luck if I don't have a 30-amp circuit already present, or if I can safely adapt down to a 15-amp circuit.

While technically the UPS will not likely draw much of a significant load itself if there are no devices plugged into it to charge the battery/batteries, you would safely be under the limit of what the 15A circuit can supply. It is all the devices you plug into the UPS is what draws the maximum load from the circuit. Thus the rating on the UPS is for how much the UPS can handle under load. So if your devices are working fine plugged directly in the 15A circuit, you would not be drawing any bigger load by putting the UPS into the chain and it would be safe to use it that way.

However, the problem is that those connectors are used to guarantee safe usage when the load does get higher (you start adding more devices than you have now) and you are now approaching the limit. The breaker on the 15A circuit should trip way before you actually reach that high of a load, so again, you would technically be safe. But the big problem is that this would be a violation of electrical and fire codes in most places and if caught doing this, you could be subject to safety violations or fines. So do not recommend doing it.