2005 Mazda 3 SP25 is using too much oil

That’s not a bad innings for a four-cylinder engine, even a modern one (although I’ve seen similar engines with more kilometres and still going strong). There’s a fair chance the piston rings and valve stem seals have lost some of their mojo and are allowing the oil to be burned in the engine. It’s normal wear and tear, but it needs to be fixed on the basis of the pollution being produced from the tailpipe. Also, eventually, something major will fail spectacularly and leave you stranded.

Your options include rebuilding the current engine or finding a second-hand engine with fewer kilometres on board and simply swapping it into your car. Thanks to the fact that the Mazda 3 was a popular car with younger drivers, they’re somewhat over-represented in wrecking yards, often with engines in very good condition. This would certainly be cheaper than rebuilding your current engine.