I've been an auditor. I started my accountancy life back in the early 80s before "modern" audits were a thing. Back in those days, in the small accountancy practice I worked in, we "audited" everything, whether strictly necessary or not, including sole traders such as shops, tradesmen, cafes, private hotels, etc. Our "audit" wasn't the modern style of sampling etc., we just checked everything, ticked off the bank statements, ticked off the invoices, ticked off the till slips, etc. It was just "normal" and part of doing the job properly. The firm's partners didn't want any accounts to be signed off without them being "right".
As time passed and I moved firms, I ended up in a bigger firm that did "proper" statutory audits and couldn't believe how shoddy and slapdash they were. No real interest in the accounts being right - it was all about the "audit trail" of the audit work we did, i.e. planning our audit, recording what we'd done, recording the sampling we'd done, recording the "walk through" system checks we'd done, etc., all aimed towards satisfying the regulators that we'd "properly planned controlled and recorded" the audit work as required by Auditing Standards. Never once was there any "sanity check" to prove the accounts were actually right - it was all about following procedure and obtaining evidence to prove that we'd done checks.
On two notable occasions of large firm audits in practices where I worked, the accounts turned out to be blatantly wrong, but our "audit" work hadn't even scratched the surface to identify the errors. Both cases led to the firms in question ultimately going into receivership, people losing their jobs and innocent suppliers losing shedloads of money. A "sanity check" type of "old fashioned" accountancy would have highlighted the errors, but because nothing came up on the modern "risk based sampling" approach, the firms in question happily signed off the audit reports which meant the firms got continued/extended banking facilities, loans, new suppliers provided goods on credit, landlords gave them leases for premises, firms provided equipment on HP/lease etc - all ended up suffering big losses!
It was that kind of experience which led to me leaving "audit" firms and starting my own accountancy practice and cancelling my "auditing certificate". I didn't want anything to do with the "industry" of modern audit which is basically box ticking for regulators. Now I'm about to end my working life as I head into my 60s and for the past decade or two have been proudly back to doing accounts the "old fashioned" way again, of actually just "ticking and bashing" and doing my utmost to actually produce a set of accounts that is actually right, every figure subject to a "sanity check" without worrying about the nonsense of materiality, creeping materiality, etc. To my old-fashioned mind, accounts are either right or they're not, and I don't indulge in the concept of them being "materially" right where materiality is an arbitrary concept and can disguise big problems within the firm.