The assessment for whether Chrome qualified as a gatekeeper is less than 3 pages long. All they care about is whether they qualify as a platform and that they are over the threshold for active non-business users, active business users, revenue in the EU for enough time.
At no point did they concern themselves with potential anti-competitive practices in making the determination.
It's only after they're designated a gatekeeper that they're required to avoid things like self-preferencing or negotiating MFN terms with business. This conveniently allows the EU to pick and choose who the restrictive rules apply to on a company by company and product by product basis.
https://ec.europa.eu/competition/digital_markets_act/cases/2...