Degraded performance firestore ONLY in safari 26.4

### Operating System

ios 26.4,macos 26.4

### Environment (if applicable)

safari 26.4

### Firebase SDK Version

12.11 / 11.10

### Firebase SDK Product(s)

Firestore

### Project Tooling

Angular 19, firebase (JS SDK) 12.11, Ionic 8, Capacitor 7, TypeScript 5.8, RxJS 7.8, zone.js 0.15 — built as a hybrid web/native app targeting iOS and Android via Capacitor.

### Detailed Problem Description

Only on Safari 26.4 (macos OR ios) bigger firestore calls take way longer than on any other browser. On Safari 26.2 everything is fine.

I tried updating from firebase 11.10 to 12.11 -> No Fix
Happens with straight up firebase-js-sdk OR angular/fire

Loading a bigger document like this:
const docRef = doc(this.firestore, `${collectionName}/${id}`);
const response = await getDoc(docRef);

In all browsers takes sub 1s

In Safari 26.4 it takes various different amount of times. But usually around 10s.

Here are the verbose debug logs about it: (both from the same machine with the same internet connection)
Safari 26.4

Chrome:

On the same machine on the same day the same document loaded fine with 26.2, after the update to 26.4 it started doing this.

Is anyone else experiencing issues like this?

### Steps and code to reproduce issue

Sadly I don't have this