Yes! this is an excellent one that I did miss, because there is no occurrence of anattā in it, but it is one of the best and most direct articulations of anattā in the canon.
I am afraid I will have to get back to you, as this might change everything I have been saying (for starters the parallel is in MA)
probably the first thing to say is that MN22 is one of the rare occurrences of anupalabbhamāne (“not a genuine fact”) which occurs only here and at SN22.85 and SN44.2 in the EBT’s.
sabbaṃ viññāṇaṃ (all consciousness) does not occur in DN, and in MN only occurs here (MN22) and the previously mentioned MN35 and MN109, it occurs once in the Vinaya, 3 times in AN, zero times in the early books of KN, never in the Abhidhamma, and 17 times in SN.
yampi taṃ diṭṭhiṭṭhānaṃ occurs:
VN: 0
DN: 0
MN: 1 (MN22)
SN: 0
AN: 0
KN: 0 (including the late books)
AB: 0
VM: 0 (Visuddhimagga)
paripūro bāladhammo occurs:
VN: 0
DN: 0
MN: 1 (MN22)
SN: 0
AN: 0
KN: 0
AB: 1 (qouting MN22)
VM: 0
attaniyaṃ me occurs:
VN: 0
DN: 0
MN: 1 (MN22)
SN: 0
AN: 0
KN: 0
AB: 1 (qouting MN22)
VM: 0
na uppajjeyyuṃ sokaparidevadukkhadomanassupāyāsā occurs:
VN: 0
DN: 0
MN: 1 (MN22)
SN: 0
AN: 0
KN: 0
AB: 0
VM: 0
diṭṭhinissayaṃ nissayetha yaṃsa diṭṭhinissayaṃ nissayato na uppajjeyyuṃ occurs
VN: 0
DN: 0
MN: 1 (MN22)
SN: 0
AN: 0
KN: 0
AB: 0
VM: 0
ttavādupādānaṃ na samanupassāmi yaṃsa attavādupādānaṃ occurs:
VN: 0
DN: 0
MN: 1 (MN22)
SN: 0
AN: 0
KN: 0
AB: 0
VM: 0
pariggahaṃ pariggaṇheyyātha occurs:
VN: 0
DN: 0
MN: 1 (MN22)
SN: 0
AN: 0
KN: 0
AB: 0
VM: 0
ajjhattaṃ asati aparitassanā hoti occurs:
VN: 0
DN: 0
MN: 1 (MN22)
SN: 0
AN: 0
KN: 0
AB: 0
VM: 0
ucchijjissāmi nāmassu…
vinassissāmi nāmassu…
tathāgatasāvakassa vā sabbesaṃ…
so loko so attā (this one is qouted in AB again)…
diṭṭhiṭṭhānādhiṭṭhānapariyuṭṭhānābhinivesānusayānaṃ samugghātāya…
taṃ vatāhaṃ na labhāmī (this one is qouted in the Nidessa)…
taṃ vata me natthi…
So evaṃ samanupassanto asati na paritassatī…
sassatisamaṃ tatheva ṭhassāmīti (this one gets a shout-out in the Kathuvatthu)…
diṭṭhiṭṭhānāni just here in MN22 and in the patisambhidamagga
So I guess I would just say that there are quite a lot of words and phrases that appear to be unique to this sutta.
Perhaps after @sujato 's Pali course I will be in a better position to asses the import of this fact.
Even antarāyikā is quite interesting;
VN: 28
DN: 0
MN: 8 (once in MN12 and all the rest in MN22)
SN: 0
AN: 2
KN: 3 (once in the Theri, then in Netti and Pet)
AB: 0
VM: 1
as is yathā yeme
VN: 18
DN: 0
MN: 6 (all in MN22)
SN: 0
AN: 0
KN: 0
AB: 0
VM: 0
Metta