I agree on getting a much better quality used bike for that budget - I do love steel as well as titanium bikes and looked at both the steel bikes mentioned here - just be aware with both the Croix de fer and the Temple Adventure bikes that the lower models of each use mechanical disc brakes not hydraulic - I know I’ve mentioned it already but particularly if planning riding much off road, the modulation and lighter touch of hydraulic is imho much nicer
Cheers and yes; that's a good point about the brakes however it's a potentially bit more nuanced than that. Can't speak for Temple but I'm very well acquainted with Genesis' range (at least up until 2020).
IIRC nowt got proper hydraulic discs until the 2018 CdF 30, which had non-series but 105-level kit. The 2019 and 2020 '30s are the pick of the bunch IMO as they both got full hydraulic R7000 / GRX. These were a good chunk more than the lower-level offerings (RRP was c. £2k) and are a lot more scarce, however don't seem to hold their value so well and you do see them come up occasionally within your budget.
As you point out none of the lower-end models have ever had proper hydro brakes, although the CdF 20 got semi-hydro with cable-operated TRP Hy/Rd calipers for most of its run from 2015-2020.
Also, probably off the menu but the flat bar version of the CdF 10 introduced in 2020 got hydros at a much lower price (no doubt thanks to this tech being ubiquitous in MTB circles for years) while the 2021-2024 '10 and '20 also got hydro brakes..
Post-2020 it all went a bit squirly as covid first knackered what kit could be got, then made it all bloody expensive. The 2021 CdF 30 was hobbled with cable discs (on a £2.3k bike!) and stuff has got a bit more sensible now, although personally I'm not a huge fan of the way they're heading and given how poor sales have likely been I suspect most of the used stuff you'll find will be earlier.