A dachshund barks to raise the alarm and to be located underground, digs to reach quarry and to make a den, and chases small fast things because that was the entire point of the breed. None of these is a behaviour problem in the dog's terms. They become problems only when they collide with flats, neighbours and roads.
The workable approach is the same for all three: reduce the triggers, give the instinct a legal outlet, and reward the alternative behaviour you do want.
Barking and digging
For barking, manage the visual triggers — window film, moving the dog away from the front door — and teach a "thank you, enough" routine where one or two barks earn acknowledgement and then a rewarded recall to you. Shouting just adds a bigger voice to the chorus.
For digging, provide a sanctioned dig zone: a sandpit or a corner of the garden with buried toys. Praise digging there, interrupt and redirect digging elsewhere. Bored dachshunds dig more, so add food puzzles and scent games.
Prey drive and recall
Assume recall will fail once a dachshund is locked onto a squirrel or a scent line. Train a strong recall with high-value rewards from puppyhood, practise it constantly below threshold, and still keep the dog on a long line anywhere near livestock, wildlife or traffic.
Channel the drive into games — flirt poles, hide-and-seek, licensed earthdog or barn-hunt style activities where they exist. A dachshund that gets to use its nose and chase on cue is calmer about the squirrels it is not allowed to have.
