I would say with a sync of 74Mbps you stand more chance of upsetting DLM by playing around to increase sync than gaining anything he would know the difference about in normal usage.
If the 3B and ASUS are working I would "think happy"

.
Neither the Huawei nor the ECI modems are top-ranking for speed now, so unless someone comes along telling you how to put the EE router in bridge mode as the modem, as you asked about, I would leave well alone.
Edit: And with the Huawei you can at least get comprehensive stats

. The ECI gives nothing useful.
My broadband basic info/help site -
www.robertos.me.uk. Domains, site and mail hosting -
Tsohost.
Connection - AAISP Home::1 80/20. 200GB. Sync 70745/12295Kbps @ 600m. BQMs -
IPv4 &
IPv6
Edited by RobertoS (Sat 01-Sep-18 00:09:35)