It seems likely that your HL2 is toast. There isn’t much protection at the RF input.
Unfortunately we cannot have main power supply *and* an external antenna *and* Ethernet without providing a path for lightning. I lost $10K worth of equipment in a strike some years back, which involved current coming in via cable internet (suspended wires in the street) and back out through main power (also suspended wires), passing through my Ethernet infrastructure and killing everything en route. Everyone in our street had similar damage, so I suspect it cost the insurance companies quite a bit.
Adding radio antennae to that means I have three outside sources - but the street wiring is by far the biggest.
What I’ve done is to create two networks; the external “hot” one and the internal one, with a 10GbE optic fibre isolating them. The radios are on the hot side, but all my IT infrastructure is on the cold side.
I disconnect the antennas when not in use, but I feel that with gas discharge tubes and proper limiter diodes at the radio inputs, I could survive all but a direct strike. In 2019 I redesigned the HackRF to use several Skyworks SMP1330-085LF diode, and if I was revising the HL2 I would do something similar at the receiver input.
Consider putting the radios on battery power to reduce the exposure to mains wiring.