In 2020 COVID decimated Rolls Royce given their concentration of revenue associated with selling & servicing existing aero engines.
They have yet to recover from that era which saw a ~10x decrease in enterprise value and record losses.
That said I would interpret this news as a "cut the $!@$! R&D bleeding in anything that won't be generating revenue in the next 4 quarters" vs a reflection on the feasibility or health of Boom's very early but very ambitious plans.