Some authors aren’t familiar with the difference between “the Gentry” and actual Peers of the Realm. Avoid confusing them; finicky readers will notice.
Here’s how Wikipedia explains it:
Landed gentry is a largely historical British social class consisting of land owners who could live entirely from rental income. It was distinct from, and socially “below”, the aristocracy or peerage, although in fact some of the landed gentry were as wealthy as some peers.
They often worked as administrators of their own lands, while others became public, political and armed forces figures. The decline of this privileged class largely stemmed from the 1870s agricultural depression.
The designation “landed gentry” originally referred exclusively to members of the upper class who were landlords and also commoners in the British sense, that is, they did not hold peerages, but usage became more fluid over time.
Similar or analogous social systems of landed gentry also sprang up in countries that maintained a colonial system; the term is employed in many British colonies such as the Colony of Virginia and some parts of India.
By the late 19th century, the term was also applied to peers such as the Duke of Westminster who lived on landed estates.
The book series Burke’s Landed Gentry recorded the members of this class. Successful burghers often used their accumulated wealth to buy country estates, with the aim of establishing themselves as landed gentry.
(The bold type is my emphasis.)
In Regency and Victorian England – and even today, in some social circles – peers may be held in far higher esteem. “Landed gentry” might be considered nouveau riche. It varies with the context of your story.
Also, remember that snobbish attitudes are more likely observed among the “top of the trees” upper class and among servants and lower classes. (However, that’s a stereotype and not an absolute rule when creating your characters.)
Between those extremes, attitudes varied by background and personal priorities, even within a household. For example, in Pride & Prejudice, Mrs. Bennet was very vocal about income and holdings; Mr. Bennet seemed cheerful about accepting people based on their finer qualities.