Defining stride or ragtime musically might be futile, altho, if I were
writing a book on it, I would just do it, much like people tag animals
in order to have a gig tagging animals ...

IMO, stride is a technical piano style which derived its name from the
way the players' hands strode (italics mine) across the keys, raked,
loped, jumped across. When you (try to) play tenths, broken or not,
and then hit that chord (the pah of oom-pah) on the two beat,and you
do this fast and fluidly, you are striding. It should be noted (I
volunteer) that stride is technically related to a corney, but
difficult piano style of rendering certain sentimental pop songs as
one-person band endeavors--songs which were not all that syncopated,
and devoid of blues and/or jazz influences but played in a frantic
polka time ... in other words, white music.

Technically, in addition to perpetual syncopation, stride is
swingified more than rag is, or probably can be and still live. That
is, the swing effect, of adding a certain triplet feel (jazzy), is
almost necessary in order to keep the thing happening. It slows the
effort down, in playability, if not in tempo, where you most need it:
just before jumping to the two-beat chord. The swing feel may have, by
the way, IM(humble)O, evolved from players with weak ring fingers
unable to play scales or melody lines in discrete rhythmic increments
per classical style.  The undeveloped ring finger, glued to its
tell-tale tendon, rushes the note, and, viola, swing.

One very swingy guy is Blind Blake, who imitated Strideists on his
guitar.  Cripple Clarence, a boogie person, plays very swingy right
hand riffs against a driving mechanical left hand--very powerful.  The
best stride has a balance of swing and drive, which are synergistic.
Fats Waller was perfect this way.

I think both Rag--notwithstanding the noble attempts to classicize,
classify, and classize it--and Stride are folk music, albeit, evolved
folk music. They can never shed their origin. Or, when they do it's,
well, academic.