There's no single "force Wi-Fi strength" switch in LineageOS, so it depends on what you're trying to achieve. Two common cases on a Fairphone 4 (whose punch‑hole camera often crowds the status bar and hides the Wi‑Fi icon):

1. Wi‑Fi icon keeps disappearing from the status bar This is not a bug — Android only hides system icons like Wi‑Fi, alarm, or battery when the right side of the status bar runs out of room (the same behaviour reported on other LineageOS devices, where disabling e.g. alarm icons makes the Wi‑Fi icon come back XDA Forums). To force it visible:

• Reduce other status‑bar icons: Settings → System → Status bar → disable things you don't need (battery percentage, network traffic monitor, etc.).
• Turn off unused alarm icons and limit notification icons (a "dot" in the status bar means icons are being hidden due to lack of space XDA Forums).
• Check Developer options → "Status bar location indicator" is off, as extra indicators eat space Reddit.
• Reduce display size (Settings → Display → Display size → smaller) to fit more icons.

There is no setting to pin the Wi‑Fi icon permanently — if it's hidden, it's purely a space issue.

2. You want the actual signal strength (dBm) instead of/next to the bars LineageOS can't display RSSI numbers in the status bar natively. Options:

• See it on demand: Settings → Network & Internet → Internet → your connected network (tap the gear) — it shows "Signal strength" in dBm. Or Settings → About phone → Status.
• Enable Developer options → "Wi‑Fi verbose logging", which among other debug info helps when checking signal quality RouterHax.
• Install an analyzer app (e.g. WiFiAnalyzer from F‑Droid/Play) that shows live dBm per network, roughly −50 dBm excellent, −70 borderline, below −80 unusable SpeedtestHQ.
• For a numeric value permanently in the status bar, LineageOS only offers the network traffic monitor (Settings → System → Status bar), which shows upload/download speed, not RSSI Reddit.

If you meant something else (e.g. the Wi‑Fi icon showing an "X" / no‑internet mark, or forcing a connection to a weak AP), let me know and I'll dig into that.