Hi
I have just received a G2 which will be first foray into VR. I'm afraid I haven't used it yet as I've been usper busy this week but here's a couple of quick answers. I can update after the weekend once I've used it.
G2 has received mixed reviews about "tracking" but invariably these related to the tracking of the hand controllers. In games like beat saber but moreso FPS games holding the controllers close to the face or by your sides can cause a loss of tracking of the controllers (according to some people...) However assuming you play DCS with some kind of HOTAS this tracking is a non-issue to you ingame. The only tracking there that counts is the headset tracking which is generally considered to be very good, with points made above about needing some light in the room.
In terms of pricing, it's been on pre-order for many months and only launched in the last 2-3 weeks, there's still a bunch of people who pre-ordered in July / Aug who are only just receiving them. Like the CPU / GPU/PS5 releases recently lack of demand leads to Ebay scalper prices
System Active are the approved dealer for preorders in the UK but they have a big backlog of orders and enw ones are likely not fulfilled till next year. I have seen reports that HP UK are selling from their website with near immediate delivery, if they have any left they should be at MSRP. (Edit: Just realised it looks like you have already checked HP UK website)
I can update with my new to VR experiences later this weekend, although I'm running it with a slightly underpowered GPU (5700xt) so not ideal.
Hope this helps...