hello
maybe you can truncate your FIR filter if you can afford some tolerance in how the filter curve behaves in the lower frequency range (depends of your application)
splitting in two may not give you any benefit because shorter filters = less accuracy in lower freqs and having two instead of one filter may not be as accurate as the original filter anyway
or you could change to IIR filter for a much more compact realization (implement it as SOS (biquad) sections)
