My impression is that commercial loan securitization is a little different.

When you're talking about residential mortgages, you're talking about loans of a few hundred thousand, which is kind of too small for capital markets to bother. So the banks bundle them, like you say, and sell them in $1e8-1e10 offerings.. Pension fund's gotta park $100,000,000 somewhere, and that MBS is easier than actually managing 500 separate loans.

When you're talking about commercial real estate - and especially things as big as data centers - it's the opposite problem. They need such big loans that only a big bank or even consortium of big banks can get all the capital together, then the big bank turns the loan into a bond offering, so investors can buy them in slices as small as $1e4.. That bond may only have one or two loans in it, so it can't necessarily get broken into risk tranches like the MBS.