LTE connection is always in for surprises in some countries.
Last week one ISP had a problem. 8.8.8.8 was not reachable , but 8.8.4.4 was. Half of the internet was reachable on that link with 8.8.4.4 check.
Load balancing swapped to the SXT which uses 8.8.4.4 by the recursive route check, but that SXT link could not reach my home (management point) for 3 days.
Still had another group of SXT with another provider, so I could change the distances in the routing table, to use Starlink temporarely for my out-of-band managemant (which was now in-band)
Management uses hEX for tunnel initiation, and selects the gateway with http://forum.mikrotik.com/t/advanced-routing-failover-without-scripting/136599/1 failover. (recursive route check)
Clients use Draytek + TP-Link RT480R load balancer, but that will be replaced by Powerbox Pro and the complex load balancing (complex because Starlink is now the best, the SXT use LTE-Limiter script to swap between SIM cards, based on fair-use limits and corresponding speed limitations. That script tries to have always connection (enabling the LTE interface even with limited speed, enabling masked bands if no connection … some connection is better than no connection for out-of-band management). Rules are different for user data, seeking the highest speed.
But when the test gateway is OK, and the needed links are not reachable , the scripts failed. If recursive route check fail was detected, then the swap to Startlink would have been automatic.
Cost is important, therefore the SXT LTE kit , which is better than the SXT LHG for low frequencies. (I lost the URL to the antenna diagrams) . ATL was not available at that time and is today beaten by Starlink in cost and performance, in France.
On more story telling: FREE (ISP) uses band B28 (700MHz) as preferred band, but never introduced a handover to that band, as the SXT LTE Kit does not support it. (I expect the same to happen for masked bands.)