The bracket extensions you posted are for when you buy a TV with a larger VESA spacing but want to continue using a bracket who's normal VESA spacing doesn't extend far enough, so they're not intended for the job you want but they might be suitable, depending on a few things.
I would envisage you needing two of those extension bars to extend the lower VESA holes on your bracket, so does your current bracket allow for the top bolt to be used further down ? Are there slots or holes further down, towards the centre ? If so, the difference between where the bolt is now and the lowest point you can use it will be the maximum amount you can lower the TV using adaptors like the ones you linked to.
If that distance is far enough to make modifications worth it, you would then need to get extension bars long enough to overlap the existing lower part of the bracket as much as possible and be bolted very firmly (ideally in two places, spaced apart), while also leaving a mounting point in the right place for the lower VESA holes on your TV. It might be difficult to judge whether an adaptor is suitable from a blurry Amazon photo, but you'll need to find some with a stated length that is long enough to overlap sufficiently. If the ones you posted are 18.5cm long, then that won't be long enough to lower the TV by 7" and also get a decent overlap. If the overlap is too small and/or the extension bars are too thin, then it's possible the weight of the TV might bend them.
Just bear in mind that this will alter the weight distribution and therefore forces on the bracket at the wall, so you need to be really sure it's securely mounted. Any weight recommendations for the bracket would presumably also be affected, so I wouldn't want to be too close to the maximum weight limit. It might also reduce the angle at which the TV tilts downwards.
This is only general advice based on what you've said and the photo you've posted BTW - it's hard to make specific recommendations without being there in person to see it. There'll obviously be no come-back on the bracket manufacturer if anything goes wrong, so this is very much 'at your own risk' !
If it was me, I would probably re-drill the holes and mount the bracket lower down as it would be less risky and virtually a no-cost option, but my walls are painted - I can appreciate why you would want to try and avoid this with a wallpapered wall.