Is it possible to get a linear glissando, like it is played by violins and not chromatic glissando.
Not really. It’s a limitation of anything based around MIDI… pitch bend is limited to 2 semitones.
Some VSTs will have workarounds for monophonic passages (e.g. two overlapping notes means gliss) but there isn’t a general solution.
You want a continuous sliding sound on playback rather than discrete pitches? I’m afraid Dorico does not yet support playback of such glissandos.