I would say his arguments is indeed right.
So backing to square one, I am looking for a logic analyzer with 7-8k Euro budget.
The questions I would want answered before inquiring further are:
How many logic channels do you need?
and
How much circuit (probe) loading can LPDDR1 lines tolerate before there is unacceptable signal degradation?
I don't know the answer to either question.
The Siglent SDS5104X is in your budget, the Siglent SAP1000 (single-ended) and SAP2500D (differential) probes also fit your budget and the SPL2016 logic probe is quite cheap, but has only 16 channels and 18pF input capacitance, which may not be good enough. If the logic portion is good enough for your purpose, then great. If not, then the whole package doesn't help you.
The 4-series Tek is going to be a lot more money ($20K+), but the TLP058 logic probes ($2K+ each) have 3pF input capacitance and a higher sample rate and bandwidth. You can use 4 of them for 32 channels, but your overall cost is going to be way over your budget.