There's a few claims made that are jumbled together. Without reviewing Spurs' books I'll make a few brief responses here.
1. Stadium build costs are usually excluded from PSR; I don't know what Spurs books and PSR reviews look like, but this is the standard
2. We know that Levy was holding down operating costs when building NWHL (or whatever it's called); not sure if this was for the benefit of PSR, but less costs = PSR benefit
3. Everton were not charged on stadium costs, but loans used for stadium costs that were alleged inappropriately booked/reported; without getting into all of that again, it's not as though Everton have a different set of rules applied vs Spurs (*again, not getting into all of that)
4. All assets are depreciable, that's not anything new; depreciation begins from when the asset is purchased/built, etc; you can't depreciate construction, you depreciate what you own. there's not secret advantage or loophole here.
5. Not sure what old Everton accounts show, but once you depreciate an asset you can't depreciate it again; a 125 year old stadium has fully run out its deprecation; the Park End rebuild in 1994 for £1.3 million would have been depreciated over a fixed term, but those are likely to be the last depreciable* assets on the Everton accounts, lawnmowers notwithstanding
So to suggest that Spurs are exploiting a loophole is probably ignorance or maybe bias, but there's no actual evidence for this, even if you disagree with the PSR deductions held against Everton
*depreciable stadium assets, I'm sure the club has lots of depreciable assets