Caveat: have only worked with SRAM and have only done the following from the caliper end.
I need to internally route (through some new handlers) and shortern R7020 cables.
Can this be done easily at the lever end? It seems that Shimano uses an olive/barb at the lever end (different to SRAM) and caliper end.
The manual [https://si.shimano.com/pdfs/dm/DM-RADBR01-07-ENG.pdf] suggests you can shorten from the lever end (avoids having to deal with the internal routing on the frame) but they use a very elaborate and expensive tool, the TL-BH62.
Is the TL-BH62 necesary? It seems the same could be done with a dedicated cutter (already own) and a barb press, e.g. this for £16 https://www.wiggle.co.uk/lifeline-pro-hydraulic-hose-needle-driver/