in europe the lenovo thinkbook is the cheapest offering for a good laptop with thunberbolt 4 and yet come with 800euro price tag, AMD even with good CPU perf won't offer Thunderbolt .

Not really. Thunderbolt is now being pushed down onto low-end mainly because Intel is being desperate, and you can also find ultrabooks with better ports in this weight class.

This laptop would be competitive at $650 with 16GB, not $950, because that's how good AMD laptops are right now. You can find one with similar components (display, wi-fi, battery etc) with 16GB of RAM for as low as $600 with a discount, with much better performance with Ryzen Zen 2/3.

$700+ USD will usually get you "the bare minimum" which is 300 nits, 70% ARGB display and a 50+ Wh battery.

Lenovo's just being cheap here, shooting themselves in the foot.

I think this laptop has pretty specific target audience. The review unit has 16GB RAM, pre-installed Windows 10 Pro and 512GB SSD, resulting in 800 Euro. This is already in the cheappo territroy, and if you go let go all of these (i.e. Windows, additional RAM on SODIMM slot, bigger SSD) and upgrade it with something you already own, it could go down to 500-ish Euro, effectively entering the super cheappo territory.

Usually, cheappo laptops don't carry Thunderbolt, and super cheappo almost never carries Thunderbolt, because target audiences probably don't have multiple 4K monitors and thunderbolt docks. In other words, this is one of the cheapest laptop with Thunderbolt. Obviously, someone who use this laptop almost exclusively with Thunderbolt dock probably don't care much about screen quality or battery life. In this use case, low price tag at the expanse of poor screen and battery is more than welcome.

Also, good battery life is not neccessarily a good thing, especially for certain audience (someone who almost never use it on battery, or only for short duration). There are roughly three ways of getting good battery life, and every manufacturers use a combination of them.

Bigger battery is a straight up solution which gives you longer battery life without performance drop, but it is almost certainly heavier and leaves less room for other interanl parts. It is also somewhat more expensive.

Using low power parts (not just CPU, but also display, RAM, SSD, WiFi module, etc) gives you longer battery life without the weight penalty, but this approach introduces a steeper price tag and there might be some performance drop.

The other common method is aggressive power management scheme, both on software and hardware level. This provides a longer battery life without getting any heavier or costlier, but comes with moderate to severe performance drop (in some cases, not configurable by user).

45Wh battery capacity is low end of the spectrum, but the battery life is much worse than similarly spec'ed laptops. This and relatively higher performance suggests that it has relatively performance-focused power management scheme. This is a good thing for someone who doesn't use it on battery often. Someone who needs more juice could go 60Wh at the expense of expandable 2.5" cage.

The other thing I notice is relatively good port configurations with some reinforcement, which is rare thing at this price point.

However, according to Lenovo, it's HDMI 1.4b, not 2.0. This is no problem for someone who use this laptop with TB dock or TB monitor. But for someone who regularly use a regular 4K external monitor via HDMI without TB dock, it could be a hassle.
psref.lenovo.com/Detail/ThinkBook/ThinkBook_14_G2_ITL?M=20VD008WGE

Why can't Lenovo keep RJ45 and full size SD reader in ThinkPad line machines with a bright matte 16:10 screen? That's what happens when marketing people make decisions instead of engineers.

One of the Notebookcheck privileged companies strikes again... How the hell this crap laptop with subpar screen and low battery life gets 84%

Because Windows 10, that's why. These tests are only accurate for a given SKU in a given month, things could swing - good or bad - at any point (read: when a monthly QU drops).
We said feature updates every 6 months was too frequent; so they merged major updates into QFE's. Now, "Chaos is me".
I spent months tracking down energy consumption issues & wake-up events on our machines, all to no avail. Surviving the initial, post-OOBE updates is always easy; come back to that PC 1.5 years later, and MY GOD, you'd fight the urge to re-image. My own personal HP can live anywhere between 5 and 12 hours, doing the exact same playback routine. Same journal contents, same app activity, wildly different powercfg graphs.
TL;DR: I agree, there's no reason for this platform to die so quickly (unless the battery is mislabeled and is, in fact, 67% of its advertised capacity).

why can a laptop with integrated graphics, U-series processor, and below 250-nit display have such a poor battery life...

If battery life scales, it would die before 8 hours in Edge wifi web browsing test even with 60 whr battery...