If you really want 'easy' &/or cheap, you could always use a rod or bit of wood cut to the right length to serve as a prop - measure from an inside bottom corner of the compartment up to the same corner's inside top of the lid while it's open to get the max length for your prop.
OR maybe even just clip a spring clamp onto the top edge of the lower half of the compartment once it's open - then move the clamp right back along the edge until it's handle hits the underside of the lid!

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There's potentially lotsa cheap & easy ways if you put some thought into it; but for my 2 bob's worth, I'd be replacing tghe strut!

hyea: . There's probably even a thread here already that has a part number if you want to search for '
trunk; + gas; + strut' & then do some light reading (there's only 2 pages of results! :shocked: )
Over to you. :thumbup: