Unfortunately, the ADSL hardware situation is not great. There are a few devices that can run OpenWrt, but I believe none of them are currently being sold. If you can find one, second hand, that would be a good way to go. However, you will most likely just have to find a new device that is still actively supported and accept that it has a closed firmware.
What country do you live in? It may help to identify what type of DSLAM you will be connecting to. ADSL modems that use a Broadcom chipset often provide the fastest and most reliable connection, but it depends on the DSLAM.
If you buy one of the TP-Link modems, make sure you get the latest hardware revision; they have a history of releasing new versions and abandoning the previous one, in terms of firmware updates. Last time I looked, the TP-Link modems all used TrendChip chipsets.
Personally, I would get the cheapest Draytek router I could find and put it in bridge mode. In my experience, Draytek do a better than average job of providing firmware updates.
Alternatively, if you don't mind double NAT, you can continue using your FritzBox and just connect your new AP to it.
On a separate note, if you are paranoid about products from Google and Amazon, you should probably be even more paranoid about products from companies like TP-Link, IMO.
If you go for the two device solution (adsl-modem + new router / aDSLrouter + new router) and you also want to be future proof, you might wanna check out devices that support Wifi 6 (ax). Wifi 6 promises enhanced stability and lower latency. On paper, Totolink x5000r seems a nice option if you look for "mid-range". In Germany, you can get it for as low as 60€, but since these ax devices are pretty "new", there is a risk of running into unknown bugs of course. I checked Github for bug reports and would advice to run the snapshot, rather than 21.02 stable.
That model has similar board layout as DIR-878, DIR-882, DIR-2640 ... Reference
You can refer to the current discussion about 5GHz WiFi issues at GitHub
I ran into the 5 GHz bug mentioned at GiHub approximately four? days ago using a fairly recent snapshot release.
I stopped testing/using stable releases since I encountered 5 GHz WiFi issue in matter of hours compare to snapshot releases, which can last days before bug appears.
Keep in mind, common simple workaround is to release switch to 2.4GHz then switch back to 5GHz immediately. Simple enough to do with android phones and what not. However, rather annoying if users have to conduct the same procedure with their wireless connected media/streaming box(s) and/or smart tv(s)...
So am i missing something here? is mt7621 equivalent to mt7613/mt7615?
Though, i do see a report for a different model with same chipset as DIR-2660
But strangely i dont see any issues in 5Ghz wifi for 4-5 of my connected clients since the last 3 weeks of uptime of my DIR-2660.
Is it that the issue is only faced at a specific configuration which i havent used yet?
I use Channel 48 (5240 Mhz) Width 80 MHz for my 5Ghz wifi.
Users who want to buy mediatek devices - just read this:
About mt76 - only mt7615 and mt7915 support is acceptable, as development is still active. For all other devices, mt76 is a piece of sh*t (random freezes, disconnections, bad performance and even worse support). If you are not interested in details - just check number of open issues for mt76 driver, how old are they and how responses look like.
OEM drivers is the opposite - ugly coding, but good performance and stability
MT7621 your CPU and Ethernet switch. There are no WiFi circuits on the MT7621 chip. A MT7621 based ac router will have a MT7612, MT7613, or MT7615 as its 5 GHz wifi chip.
Is that actually true? I thought "modem-mode" was removed but pass through is still there, so "all" one needs to do is not to configure the fritzbox itself with the correct PPPoE credentials (preferable no credentials at all) and click the "Angeschlossene Netzwerkgeräte dürfen zusätzlich ihre eigene Internetverbindung aufbauen (nicht empfohlen)". box... Which should result in working PPPoE passthrough. But that only helps if the OP actually uses PPPoE .
True, but if your ISP uses PPPoE you really do not need a true bridged-modem configuration, it should be enough to enable PPPoE pass trough while not configuring user and password for the router itself (this was reported as working for users of recent FritzBox's as of last year). You still will need to deal with potential VLAN issues.
I would probably try that first because:
a) newer DSL routers put emphasis on the VDSL2 part and the ADSL part is not that relevant anymore so sees few updates
b) you have that device already so testing should be quick and easy, once you have a new OpenWrt router... (such a setup also allows to place the "modem" as close to the socket (TAE?) as possible to reduce additional extension cords, and to place the router optimally for the WiFi coverage, you will need an ethernet cable between modem and router though )
But maybe you could tell us which ISP and country we are talking about here?
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