Pretty sure not believable. Glassdoor gives starting salaries as less than half that, even in San Jose and San Francisco, and around $150k at Lyft for 4-6 years experience in that area. Are there really companies out there showering early-career engineers with 1-3X salary in benefits?
Many large companies in the fortune 1000 offer both bonuses and annual stock grants. This isn't just the case at large tech firms but some engineers I know at Discovery Communications get a 10%-15% annual bonus on top of their salary. Annual stock grants can also add up to a lot as long as you work there long enough for them to vest. Those are all included in TC but are not considered salary, nor are they always fully accounted for in Glassdoor's numbers.
It's also why Netflix is notorious for high base salaries because they don't do bonuses, stock grants, etc... and instead provide it all to their employees as cash.
Of course these are mostly only done in top job markets. I'm not aware of any company here in Orlando (regardless of how big) that does annual bonuses for software engineers, and I've only seen startups that really grant equity (and not to the amount you see at levels.fyi).
*Edit:* Actually I did work for one company here that gave generous annual bonuses based on the company's profit. However it was given as an excuse to not pay as high a market value for salary (though with bonuses it did end up coming to higher than market value), but then the company got bought by a private equity firm that immediately got rid of the bonuses without adjusting salaries. So not sure I'll fall for that again.