I am in agreement with Anagkai that the problem is largely one of expectations. Depending on your group either you, or your DM, or both of you, should explain to the other players that part of the flavor of Curse of Strahd is that your characters are never truly safe anywhere. This is not just about this spell - it is a larger feature that underlies the whole campaign and they will need to accept and adapt to that, or ask the DM to change that presumption, or find another setting. Even potent high-level magic like
teleport, plane shift, and wish will not allow PC's to leave the setting, and resurrection carries with it the danger of madness.
so you can't really expect a single third level spell to mean "this keeps us perfectly safe for eight hours".
However, it may help to win over the more reluctant members of your party by (1) limiting night-time encounters and (2) emphasizing the advantages of your version of the spell.
Limiting Nighttime Encounters
According to the wandering encounter tables for Curse of Strahd,
wandering encounters should not happen more than twice in 12 hours. If your DM is throwing more than 2 night encounters at you, they are already overemphasizing the "nowhere in Barovia is safe" vibe. In this case, you may want to talk to them about actually following the rules if you are going to use a modified hut. Likewise, there should be a lower chance of encounters if you stick to the roads. That is not something you as players should necessarily know, but if your DM is not playing that way they may have to scale back.
Emphasizing the Advantages of your version of the spell
Your form of the spell offers a number of advantages over the PHB version, and it is up to you to sell these to your fellow teammates.
In the official version of the spell,
Creatures and objects within the dome when you cast this spell can move through it freely. All other creatures and objects are barred from passing through it.
But your version allows you to designate who can be in it even if they are not present when you cast it. Someone off scouting when you set up camp? No worries, you'll leave the light on for them. NPC or monster arrive when you are halfway through your ritual cast? Let the other party members deal with it while you finish. Suppose you have spotted an encounter ahead of time and don't know if it will turn out to be friendly or hostile. Send the scouts or the face ahead while you work on creating the hut that they can retreat to if things go south.
All other creatures and objects are barred from passing through it. Spells and other magical effects can’t extend through the dome or be cast through it.
The PHB hut is defensive only. But yours is a fortified structure that you can place where you want and then use to make melee, missile, and magic attacks from. Again, use your scouts to figure out where the enemy is, and then lead them to the hut that you have prepared - not for you to rest in, but for you to protect your squishy casters in during the combat. When their hordes bunch up trying to assault the gate, use your AoE spells. Your version is a bunker you can drop on a field of your choosing with one minute's notice, or if you have eleven minutes, can significantly boost your defenses without spending a spell slot.
The dome is opaque from the outside, of any color you choose
Yes, if you are trying to escape notice, you can choose a single color to try to blend in to the background. But most intelligent opponents will not ignore a monochrome dome sitting out in the middle of nowhere - they will collect reinforcements and wait outside, possibly while building fortifications of their own. But your version offers Curse-specific camouflage. There is more than one little graveyard or mausoleum by the side of the road in Barovia. When you are using it to rest and not as a forward combat post it has a much better chance of looking like the normal scenery and being ignored than the official version.