It's a known limitation of odoo - it handles both cases, tax included
and excluded easily, but not both together. There is a workaround
described here:
- \https://www.odoo.com/documentation/14.0/applications/finance/accounting/taxation/taxes/B2B_B2C.html
However,
following this approach still has a lot of shortcomings and is a lot of
work. Also, not sure if you have international clients, but if so, your
B2C customers might have to switch to tax excluded tax display if the
delivery address is outside of your internal market.
I wrote an odoo app to facilitate B2C (mostly) tax-included and B2B tax-excluded
\https://ayudoo.github.io/odoo_business_relationships/
It's
in use and solves the issues reasonably easy. It's still in Beta state
though. Of course, it will require a similar configuration like in the
odoo documentation link above with tax included/excluded pricelists and
fiscal positions. But no need to assign it for single customers, you
configure it once for the business relationship type.