Re: BREXIT was a massive and expensive lie.
Portugal allows UK passport holders to go through e-gates to speed up some of the processing, but they're still queuing up to have their passports stamped afterwards before entering Portugal. This is not treating UK passport holders the same as EU passport holders.
When EES and ETIAS come online, UK passport holders will be processed by those instead of having their passports stamped, EU passport holders won't be.
When a British passport holder travels from one Shengen country to another by land they should report their presence in each new Shengen country and be prepared to answer questions about reason for stay, place of stay, sufficient funds, etc... This is not treating UK passport holders like EU passport holders.
UK continues to use e-gates and single queues in airports because it doesn't have the space to do anything else. Likewise for goods shipments UK is waving everything through inbound because it doesn't have the infrastructure to do proper checks (smugglers' charter).